Your Repayment, Before You Apply

Numbers in hand. Now find the rate that matches your profile.

The calculator gives you the estimate. LoanGorilla gives you the actual rate a lender will offer — based on your credit profile, not a generic assumption.

How this Repayment Calculator works

The calculator uses the standard loan amortisation formula — the annuity formula — to work out what you'd repay on a personal loan:

PMT = [P × r × (1+r)ⁿ] / [(1+r)ⁿ – 1]

In plain English: P is the amount you borrow, r is the interest rate expressed per payment period, and n is the total number of payments you'll make. The result is your scheduled repayment — the fixed amount you'd pay each week, fortnight, or month.

The interest rate is adjusted to match your chosen repayment frequency. Monthly uses the annual rate divided by 12. Fortnightly uses 26. Weekly uses 52. The number of payments (n) follows the same logic — a 5-year loan paid monthly produces 60 payments; paid fortnightly, 130; paid weekly, 260. This is not an approximation. It's the same mathematics a lender uses to generate your repayment schedule.

Each payment is fully amortising — every repayment covers the interest that has accrued since the last payment, with the remainder reducing the principal. Early in the loan, more of each payment goes toward interest because the outstanding balance is higher. Later, more goes toward principal. The total interest figure is the sum of all repayments minus the original loan amount — no hidden rounding.

What the calculator cannot do is predict the rate a specific lender will offer you. Your actual rate depends on your credit score, income, employment stability, loan purpose, and the lender's current risk pricing. The calculator is a planning tool — accurate for any rate you give it, but only as useful as the rate input you provide.

How to interpret your results

• Look at total interest first, not just the repayment. Your monthly repayment tells you whether the loan fits your budget this month. The total interest figure tells you what the loan actually costs. A $20,000 loan at 9% p.a. over 5 years costs approximately $4,800 in total interest. The same loan at 15% p.a. over 5 years costs approximately $8,400. That $3,600 gap is invisible if you're only reading the repayment line.
• Use the term comparison table to see the trade-off clearly. On a $20,000 loan at 12% p.a., the 7-year option saves around $319 per month compared to the 3-year option — but adds approximately $5,100 in total interest. There's no right answer. The point is to make the call with both numbers in front of you.
• Understand why early payments are interest-heavy. A larger share of each early repayment goes to interest because your outstanding balance is still high. This means extra repayments made early in the loan term have a disproportionately large effect on total interest.
• Put interest in proportional terms. On a $20,000 loan at 12% p.a. over 7 years, interest represents roughly 31% of total repayments. The lower that proportion, the better the deal.
• Worked example. A $20,000 loan at 10% p.a. over 5 years: monthly repayment ~$425, fortnightly ~$196, weekly ~$98. Total interest ~$5,497. Total repaid ~$25,497. Loans reward discipline, not drama.

How to find a repayment that fits your budget

• Work backwards from what you can afford — not forwards from what you want to borrow. Start with the maximum monthly figure you can comfortably handle, then adjust the loan amount and term until the calculator sits at or below that ceiling.
• Test different term lengths. A 2-year extension on a $25,000 loan at 11% p.a. might reduce your monthly repayment by around $150 but add $2,800 in total interest. The calculator shows both sides — your call whether the saving is worth it.
• Switch to fortnightly if your pay cycle allows. 26 fortnightly payments per year equals 13 monthly payments rather than 12 — typically saving $200–$400 in total interest on a $20,000 loan over 5 years. Small, and entirely effortless.
• Compare the comparison rate, not just the advertised rate. A loan advertised at 8.9% p.a. with a $600 establishment fee and $15 monthly fee carries a comparison rate well above 8.9% p.a. The headline rate is a marketing figure.
• Improve your credit score before applying. The rate gap between fair-credit and good-credit applicants on an unsecured personal loan can be 4–6% p.a. — several thousand dollars over the life of a $20,000 loan.
• Borrow only what you actually need. The difference between $22,000 and $18,000 at 11% p.a. over 5 years is ~$85/month and over $1,500 in total interest. If you don't need the extra $4,000, don't borrow it.

Example Repayment Calculations in Australia

These four scenarios illustrate how loan amount, interest rate, and term interact to produce different repayment outcomes. All figures use the standard annuity formula.

Calculator assumptions

This calculator produces estimates based on the standard annuity amortisation formula and assumes a constant interest rate across the full loan term. The repayment figures and total interest amounts are mathematically precise for the inputs you enter — but your actual repayments from a lender will differ. Real loans include establishment fees, ongoing monthly fees, and other charges not captured here. Variable-rate products will change repayments over time in ways this calculator cannot predict. Lender-specific calculation conventions (including rounding methods) can also produce minor differences from the figures shown. The rate you enter is the most important variable, and the least certain — it depends on your credit score, income, employment, loan purpose, and lender pricing. This calculator does not constitute financial advice. Reviewed by the LoanGorilla editorial team — last updated May 2026.